Heat-sealable devices for marking textile articles

ABSTRACT

HEAT SEALABLE LABELS OR THE LIKE AND METHODS AND MARKING ARTICLES BY MEANS OF SUCH LABELS ARE DESCRIBED. THE LABEL INCLUDES A FLEXIBLE SUPPORT INCORPORATING A HEAT-CURING FILM-FORMING RESIN SYSTEM IN THE PRESENCE OF ALKYLOL OR ALKOXY ALKYL GROUPS AND UNDER ACID CONDITIONS, AND AN INFORMATION-BEARING MARKING PRINTED ON SAID SUPPORT. SUCH A LABEL WHEN HEAT SEALED TO A TEXTILE OR OTHER ARTICLE IS WASH- AND WEAR-RESISTANT AND WITHSTANDS THE VARIOUS TREATMENTS TO WHICH THE ARTICLE MAY BE SUBJECTED.

July 27, 1371 MEYER 3,595,139

HEAT-SEALABLE DEVICES FOR MARKING TEXTILE ARTICLES Filed March 11.,.1968

Inventor 7 a, 777 y Ada/22M QQM+W Attorney United States Patent3,595,739 HEAT-SEALABLE DEVICES FOR MARKING TEXTILE ARTICLES PeterMeyer, London, England, assignor to Polymark Limited Filed Mar. 11,1968, Ser. No. 712,029 Claims priority, application Great Britain, Mar.8, 1967, 10,949/ 67 Int. Cl. 33% 27/10, 27/34 US. Cl. 16l-229 8 ClaimsABSTRACT OF THE DISCLOSURE The present invention relates toheat-scalable labels or like marking elements for applying markings ordecorative effects to textile articles, fabrics or other sheet materialsor to leather, wood, glass, plastics and so on, and to methods ofmarking articles, for the purpose of obtaining markings or decorativeeifects which are substantially resistant to wear, and in the case oftextile and like articles are resistant also to repeated cleaning orwashing of such articles.

US. Pat. No. 3,359,127, commonly owned by the assignee herein, describesmethods and means for marking textile articles, including in particularheat transfers, wherein a temporary support receives a layer of asoluble polyamide in turn carrying a printed marking. This transfer isapplied under heat and pressure to an article to be marked in thepresence of a curing agent normally consisting of a solid organic acidmixed with the polyamide or it may be ammonium salt of such acid, whichcuring agent promotes cross-linking of the polyamide in the presence ofalkylol or alkoXy-alkyl groups so that a relatively insoluble, inert andwear-resistant layer, incorporating the printed marking is bonded to thearticle, after which the temporary support is removed. This arrangementprovides a highly resistant marking on the article which is of apermanent character and can be readily designed so as not to be liableto become degraded throughout, the life of the article even afterrepeated washing and cleaning operations.

The polyamides used may be soluble polyamides or copolyamides which canbe converted into a highly inert and insoluble form by a curing agent inthe presence of a cross-linking agent containing alkylol or alkoxy-alkylgroups, and such cross-linking agent may in some cases be a formaldehyderesin. Other compounds which can be used similarly are dispersions of anacrylic resin capable of being cross-linked at an elevated temperature.

The present invention is directed to a label or like marking devicewhich offers substantially all the advantages of heat transfers producedaccording to the abovenoted patent but which can be more economicallyproduced and which has the further important advantage that the timecycle required for applying or bonding the marking to the article to bemarked can in many cases be reduced as compared with the procedureinvolved in the above-noted patent, while, furthermore, the step ofremoving the temporary support can be avoided which results in a savingof time.

In accordance with the present invention a marking element comprises aflexible support incorporating a heat curing film-forming resin systemin the presence of alkylol or alkoxy alkyl groups and under acidconditions, and an information-bearing marking printed on said support,to provide a marking element which substantially withstands varioustreatments to which the surface may be subjected.

With such a marking element the support remains bonded to the surfaceand carries a marking or decorative pattern on the exposed surface. Theink used for producing the marking or decorative pattern preferablyemploys a medium consisting of a similar resin to that applied to thesupport so that after the application of heat and pressure the printedlabel, when bonded to a textile article, is not aifected by repeatedlaundry or dry (chemical) cleaning treatments to which the article maybe subjected.

One advantage of the present invention is that the support can be formedof a relatively inexpensive material such as paper. By using a thinpermeable paper the presence of such support after bonding the label tothe article is of no disadvantage and provides a backing for the markingor pattern carried by the label. The invention also contemplates the useof a fabric, for example a fine woven cotton fabric, or a thin foil ofplastics.

Since the marking produced on the support is visible at all times,control of the printing or other operations used for producing themarking can be more readily effected than in cases where, as in theabove-noted patent, the printed marking is overlaid by the temporarysupport and is thus not readily available for inspection, while,furthermore, the present invention otfers the advantage that printing iseffected in the normal configuration and not in reverse as is oftennecessary when the support is a temporary support which must be removedfrom the article after transfer has been effected.

The fibreor film-forming resin may consist of a solubilised linearpolyaimide of the character described in the aforesaid patent and mayconsist of a nylon-type polyamide which has been converted into asoluble form containing alkoxy alkyl groups by treatment with analdehyde such as formaldehyde, as described for example in Britishspecification No. 591,382.. Materials of this type are commerciallyavailable under the trademarks Calaton CA and CB (made by I.C.I. Ltd.,and believed to be substantially identical to the substance previouslysold under the trademark Maranyl, or BCI Type 800 resins made by BeldingChemical Industries).

Alternatively alcohol-soluble copolyamides may be used in conjunctionwith a cross-linking agent containing alkoxy alkyl groups, and in this.case the cross-linking agent may be a formaldehyde resin containingalkoxy alkyl groups.

A still further alternative is a cross-linking acrylic resinconveniently in the form of an aqueous dispersion such as that soldunder the trademarks Plextol (made by Rohm and Haas of Darmstadt) orHycar (British Geon, Ltd.).

Polyamide and copolyamide resins of the above types are soluble inalcohols or alcohol/water mixtures, and such resins may be applied inthe form of alcohol or 'alcohol/water solutions. Acrylic resindispersions may be used in the commercially available form or thedispersion may be thickened by suitable additions if required.

These solutions or dispersions are used as coating or impregnatingagents and are self-curing under acid conditions. Particularly in thecase of polyarnide solutions, they may contain an organic acid curingagent or an acidyielding compound such as an anhydride or an ammonium oramine salt. Suitable curing agents are preferably those acids orcompounds which are solid at normal temperature. A typical organic acidis citric acid or alternatively ammonium citrate can be used. Such acidsare convenient for the purpose because at room temperature they aresubstantially inactive in promoting cross-linking so that labelsproduced by coating a support with a resin solution and such a solubleorganic acid, have a satisfactory shelf life and are not liable to beaffected by long storage periods; nevertheless curing occurs rapidly andeffectively when the labels are applied to the article to be treated,such application being conveniently at a temperature of the order of 150to 250 C., preferably from 180 to 250 C., and at a specific pressure ofabout 20 to 100 lbs. per square inch.

After coating or impregnating the support and drying the coating at atemperature not exceeding 100 C. the desired pattern or marking isprinted on the support and then dried. The printing ink used may consistof a medium which also is a heat curing resin together with suitablepigments and other additions appropriate to a printing medium, and theprinting of the desired design or pattern may be etfected by any normalprinting processes, for example letterpress, oifset litho, flexographicor gravure processes, or it may be produced by screen printing.

, After printing, a continuous coating of the resin mixture may beapplied to form a protective surface on the marking element. Where acontinuous outer layer is applied as an overcoating on the printed ordecorative marking there is a higher degree of protection of themarking, and it may even be possible to use normal types of printingmedia, for example flexographic shellac-based inks.

By using labels or like devices produced according to the presentinvention it is possible to complete the application and bonding of thelabel to the article to be marked in a total period of not more than 1to 7 seconds permitting a very rapid and economical marking sequence.

Several examples of methods of carrying the invention into eifect willbe described hereinafter as applied by way of example to the productionof the label-like element shown on the accompanying drawing in which asupport 1 consisting of a thin absorbent paper is impregnated with asolution or dispersion of a resin according to one of the followingexamples and after drying may then be coated on one side with a furthercoating of the resin as shown at 2. This coating is on the under side ofthe label which is applied in contact with the surface to be marked.

The opposite face of the support 1 receives a printed pattern or designsuch as is indicated typically at 3 which is applied by a printingprocess in which the medium of the printing ink consists of a resinsolution or dispersion. If desired an overcoating consisting of acontinuous layer of the resin solution or dispersion is applied.

It will be seen that the pattern or design is produced by directprinting and that the design or pattern is visible to the operator whenapplying the label to the article to be marked. Such application iseffected by means of a suitable heat-sealing press which bonds thecoated rear surface of the support 1 to the article to be marked andefiects curing and cross-linking of the resin component of theimpregnation of the support, of the printed marking thereon and of anycontinuous layers which may be present to form a highly inert andresistant marking on the surface to be marked.

Various solutions and dispersions for use as coating or impregnatingmedia are given below by way of example together with examples ofadditional components which may be present in the coating mixtures andinks, and a 4 number of examples based on the use of certain of thesolutions, dispersions and inks are set out in detail. In all cases theparts are given by weight:

TABLE I.COATING OR IMPREGNATING TABLE II.CO'ATING OR EMPREGNATINGDISPERSIONS This table comprises cross-linking acrylic resins which maybe polymers or copolymers of alkyl esters of acrylic acid or methacrylicacid comprising N-alkoxyalkyl acrylamide. Typical examples ofcommercially available products which may be used in accordance with thepresent invention are the following:

(1) Plextol B58a (2) Plextol M17a (3) Hycar 2679' The commerciallyavailable dispersions may be utilised in carrying out the presentinvention in the form received by the makers.

TABLE III.PRINTING INKS Parts (1) Solution 1 of Table I Titanium dioxide15 Cadmium yellow 3 (2) Solution 2 of Table I 100 Phthalocyanine blue 10(3) Solution 1 of Table I 100 Carbon black 7 (4) Solution 2 of Table I100 Cadmium red 10 (5) Solution 3 of Table I 100 Carbon black 6 (6)Plextol B58a 100 Cadmium red 8 Water 15 Hydroxyethyl cellulose 1Non-ionic wetting agent 0.3

In preparing this ink the components other than the resin dispersion arepre-dispersed in the water before the resin is added.

Parts (7) Solution 2 of Table I 100 Carbon black 6 (8) Solution 3 ofTable I 100 Titanium dioxide 15 (9) An ink composition similar to inkNo. 6 but in which the cadmium red is replaced by 5 parts of carbonblack.

(10) An ink composition similar to ink No. 6 but in which the resindispersion is replaced by Plextol M17a.

TABLE III.Continued (11) An ink composition similar to ink No. 9 but inwhich the resin dispersion is replaced by Plextol M17a.

(12) An ink composition similar to ink No. 6 but in which the resindispersion is replaced by Hycar 2679.

(13) An ink composition similar to ink No. 9 but in which the resindispersion is replaced by Hycar Parts (14 =Dewaxed shellac 25 Industrialethanol 75 Chrome green 15 In preparing labels in accordance with thepresent invention any of the resins of Tables I or II may be used, andthe information-bearing marking may be produced by any of the inks ofTable III other than ink No. 14. In many cases it is desirable, but itis not always essential to utilise coating or impregnating media andprinting inks comprising the same resin. Different resins can be usedfor printing particularly in those cases where the information-bearingmarking is protected by an additional coating as in Examples III, VIband VII, or when the ink can be caused to bond strongly to the permanentsupport itself rather than the coating or impregnating resin as in thecase of Examples II and VIa.

In many cases it may be desirable that plasticisers should be present inthe coating or impregnating media and in the printing inks. In the caseof polyamide solu tions and inks containing polyamides, that is to say,the coating solutions of Table I and printing inks Nos. 1 to 5, 7 and 8,any of the following plasticisers may be used but it should beunderstood that this list is not exhaustive and that other suitableplasticisers are available and could be used.

TABLE IV.PLASTICISERS FOR POLYAMIDE MEDIA N-ethyl toluene sulphonamide,tris-dipropylene glycol phosphite, polyethylene glycol.

In the case of cross-linking acrylic resins such as the dispersions ofTable II and printing inks Nos. 6 to 13, any of the followingplasticisers can be used but again this list is not exhaustive.

TABLE V.PLASTICISERS FOR CROSS-LINKING ACRYLIC RESIN DISPERSIONS dibutylphthalate,

dioctyl phthalate,

tri-cresyl phosphate,

N-ethyl toluene sulphonamide.

The plasticisers of Table V will normally be pro-emulsified with anequal weight of water and in the presence of 1% of a non-ionic wettingagent, for example one of the products sold under the trademark Nonexsupplied by Union Carbide & Chemical Corporation.

All the printing inks in Table III including ink No. 14 are suitable foruse in the fiexographic or gravure printing processes. Inks Nos. 1 to 13are also suitable for use by the screen printing process and in thiscase the industrial ethanol may be replaced by n-butanol or diacetonealcohol.

The cross-linking agent referred to in solutions 2 and 3 of Table I andin the corresponding printing inks Nos. 4, 5, 7 and 8 comprise compoundsof formaldehydes with for example urea and melamine containing alkoxyalkyl groups which in some cases may be formaldehyde resins. Thesecompounds may be selected from the following table which illustratestypical examples of suitable compounds but is not an exhaustive list ofcross-linking agents.

TABLE VI.-CROSS-LINKING AGENTS N,N-bis methoxymethyl) uron,

tri-meth0xymethyl melamine,

hexa-rnethoxymethyl melamine,

tetra-methoxymethyl urea,

urea-formaldehyde precondensates containing methoxymethyl groups,

melamine formaldehyde precondensates containing methoxymethyl groups,

hexa-ethoxyrnethyl melamine,

urea-formaldehyde precondensates containing ethoxymethyl groups,

melamine-formaldehyde precondensates containing ethoxy-methyl groups,

N,N'-bis (methoxymethyl meta-phenylene diamine.

In preparing the solutions and dispersions based on the compounds andmixtures set out in the foregoing tables the fluid coating orimpregnating media may be prepared by high-speed stirring except wherecommercially available dispersions are used in the form received by themakers. In the preparation of printing inks the pigments may beintroduced by ball milling and additional substances such as the curingagents for example triammonium citrate or citric acid added withstirring. Coating or impregnating mixtures according to Table I or TableII may be applied to the permanent support in any convenient way as acontinuous coating or by causing a continuous strip of the supportmaterial to pass through the coating or impregnating mixture. After sucha coating or impregnation has been effected the support is dried at atemperature not exceeding that at which substantial crosslinking of theresin occurs, preferably below C. The support is then printed with thedesired information-bearing marking or pattern and the printed labels orlabel strip is then dried again at a temperature below that at whichsubstantial cross-linking occurs, generally below 100 C.

Labels produced with such resin systems are applied under heat andpressure in a suitable heat sealing press at a temperature in excess ofthe softening temperature of the resin used. At these temperatures rapidcross-linking of the resin occurs with the formation of a permanent bondto the article being marked, the bond and the label itself then beingcapable of withstanding repeated laundering and dry chemical cleaningoperations.

The following examples illustrate typical methods of producingheat-scalable labels according to the present invention and as shown onthe drawing.

EXAMPLE I A 40 gm. per sq. m. high wet strength paper of high absorbencywas impregnated with 15 gm. per sq. m. (dry weight) of a mixtureselected from Table I or Table II.

A coating of 25 gm. per sq. m. was applied to one side only, using thesame mixture selected for impregnation and the coating dried, at atemperature below that at which the resin cross-links rapidly, i.e.below 100 C.

A design was then printed repetitively, using an ink selected from TableIII, Nos. 1 to 13 using the resin selected for impregnation.

Drying was carried out at a temperature below that at which the resincross-links rapidly, i.e. below 100 C. Conveniently the paper ismanipulated in the form of a continuous strip which is formed intorolls. Labels were cut from the rolls prepared as above and were testedby being applied to a range of textile fabrics including cotton, linen,nylon, polyester, glass cloth, using a heat-sealing press givingapplication conditions of 200 C., 4 seconds, 40 lbs. per sq. in.

The fabrics with applied labels were then subjected to many cycles ofthe appropriate laundry treatment and showed good resistance up to 30-50successive treatments.

Further tests were carried out applying labels onto wool, cellulosediacetate and acrylic fabrics at 180 C., seconds, 20 lbs. per sq. in.,followed by hand washing or dry-cleaning.

These labels were still legible after 3050 treatments.

EXAMPLE II An 80 gm. per sq. in. closely woven cotton fabric was coated,substantially on one side only, with 50 gm. per sq. m. of a mixtureselected from Table I or Table II.

It was then printed repetitively on the opposite side using one or moreinks selected from Table III, Nos. 1 to 13 without regard for resintype.

Labels prepared in this way were tested as in Example I and were foundto be legible after the fabric was worn out.

EXAMPLE III A 50 gm. per sq. m. viscose non-woven fabric was impregnatedwith 20 gm. per sq. m. of a mixture selected from Table I or Table IIfollowed by coating with a similar mixture to about 30 gm. per sq. -m.on one side only.

A repetitive design was then printed on the uncoated side using inksfreely selected from Table III, Nos. 1 to 14. The printed side was thencoated with a further 15 gm. per sq. m. of the mixture used forimpregnation and coating.

Labels cut from these rolls were tested in a similar way to Example I,and were found to be legible when the fabric was worn out.

EXAMPLE IV A 45 gm. per sq. m. high wet strength, highly absorbentpaper, comprising of carbon black, was impregnated and coated as ExampleI. This was then cut into sheets of a suitable size for screen printing.

It was then printed with an ink selected from Table III., Nos. 1 to 13,but of the same resin type used for impregnation, with industrialethanol replaced by n-butanol.

It was tested in the same way as Example I, with similar results.

EXAMPLE V A 35 gm. per sq. m. high wet strength, highly absorbent paper,was impregnated with 18 gm. per sq. m. of an ink selected from TableIII, Nos. 1 to 13. It was then coated with 30 gm. per sq. m. of amixture selected from Table I or Table II, using the same resin type.

Printing was carried out using a contrasting colour selected from TableIII, Nos. 1 to 13.

It was tested in the same way as Example I with similar results.

EXAMPLE VI (a) A 100 gm. per sq. m. high wet strength paper of lowabsorbency was coated on one side only with 50 gm. per sq. m. of amixture selected from Table I or Table II.

It was then printed on the other side using an ink freely selected fromTable III, Nos. 1 to 13.

These labels were intended for use by a linen hire organisation and areintended to carry in addition to the printed information individualmarkings. Cut labels were applied on to cotton or linen overalls at 250C., 4 seconds, 60 lbs. per sq. m. in., and after application additionalinformation was inserted such as the name of the lessee, date ofcontract, etc., by means of a laundry marking ball point pen (assupplied by Scripto Ltd). Labels formed in this way were found towithstand about 50 laundry operations.

(b) By applying a transparent, unprinted transfer layer applied from atemporary support, as a protective covering, preferably using the samecoating solutions or dispersions under the same conditions, the labelcould be made to last throughout the useful life of the garment.

Such transfer layer was prepared by coating a 60 micron film ofcellulose triacetate with 15 gm. per sq. m. of a mixture selected fromTable I or Table II and then dried. The dried coating was placed incontact with the label and subjected to heat and pressure under the sameconditions as the labels, and the support film peeled off or allowed todetach itself.

EXAMPLE VII A 38 micron film of regenerated cellulose was printed withan ink freely selected from Table III, Nos. 1 to 13 and then coated onboth sides with 20 gm. per sq. m. of a mixture selected from Table I orTable II.

It was tested in the same way as Example I and found to offer similarresistance to repeated laundering.

EXAMPLE VIII Labels were prepared in a similar way to Example I using acoating solution selected from Table I with three parts of a plasticiserselected from Table IV.

EXAMPLE IX Labels were prepared in a similar way to Example I, using acoating mixture selected from Table II with 10 parts per parts of resindispersion of a plasticiser selected from Table V.

It will be understood that labels according to the present invention maybe economically produced since an inexpensive class of support materialmay be used, typically a soft and absorbent paper, which is coated orimpregnated with the resin solution or dispersion in fluent form, andthen dried. Because of the absence of a temporary support theapplication of heat from the presser means used for applying it to thearticle to be marked is operative rapidly, permitting the applicationand bonding of the label to the article to be effected in a period ofnot more than 7 seconds at most in practical cases. Because the printedmarking on the label is visible at all times, control of the printingduring production of the labels is facilitated, and this easy visibilityis also of advantage in facilitating the correct application of thelabel to the article to be marked. All these factors contribute inproviding a low cost procedure for producing marking elements havinginformation-bearing markings printed thereon. The resin component ofthese marking elements is converted into an insoluble, abrasionandwash-resistant compound by heat and pressure. The printing ink itself iseither converted into a similar compound or the printing ink isprotected on each side by continuous layers of such cured compounds. Theresulting marking elements are highly resistant to influences operativethroughout the life of the article being marked, including resistance towear and resistance to cleaning operations such as cleaning solvents,without substantial degradation of the information carried by themarking element.

In some cases it may be desired to improve the appearance of the labelsafter application to the article by utilising a presser member operativeon the exposed surface of the transfer which embodies an engravedsurface pattern or grain which may give a characteristic appearance, forexample, a natural textile appearance, to the label while in position onthe article.

What I claim is:

1. A marking element permanently attachable by heat and pressure to asurface to be marked, comprising a paper-like flexible permanent supportsheet completely impregnated with a heat curing film-forming resinsystem, a further coating of a heat curing film-forming resin system onone side of said support and an information-bearing marking imprinted onthe other side of said support, said marking also including a heatcuring, filmforming resin system and said film-forming resin systernsselected from the group consisting of soluble polyamides, solublecopolyamides, and cross-linking acrylic resins and including alkylol oralkoxy alkyl groups under acid conditions for conversion of said resinsystem under said heat and pressure into an inert, insoluble andabrasion-resisting substance in situ on the surface to be marked.

2. A marking element according to claim 1, wherein theinformation-bearing marking is produced by means of a printing inkincluding a cross-linkable resin system.

3. A marking element according to claim 1, wherein theinformation-bearing marking is protected by a transparent protectivelayer on the exposed surface.

4. A marking element according to claim 1, wherein the resin systemconsists of a soluble polyamide in the presence of alkylol or alkoxyalkyl groups such that at said temperature above the softeningtemperature crosslinking of the polyamide occurs with the formation ofan inert and insoluble compound bonding the label to the surface to bemarked.

A marking element according to claim 4, wherein the soluble polyamideconsists of a methoxy methyl derivative of a polyamide.

6. A marking element according to claim 4, wherein the resin systemincludes a soluble copolyamide in the 10 presence of a cross-linkingagent containing alkoxy alkyl groups.

7. A marking element according to claim 6 wherein the cross-linkingagent is a formaldehyde resin containing alkoxy alkyl groups.

8. A marking element according to claim 1, wherein the resin systemincludes a cross-linking acrylic resin.

References Cited UNITED STATES PATENTS 2,096,750 10/1937 Lawrence117-685 2,631,947 3/ 1953 Kline 117-122X 2,853,404 9/1958 Weinberg117-122 2,927,865 3/1960 Lewis et al. ll7-15X 3,301,696 1/1967 Taube eta1. 117-15 3,359,127 12/1967 Meyer et a1. 117-34 JOHN T. GOOLKASIAN,Primary Examiner R. A. KILLWORTH, Assistant Examiner US. Cl. XJR.

